Electron energy distribution in HiPIMS discharges: analytic and numerical modeling

Sara Gallian, Jan Trieschmann, Thomas Mussenbrock, William N. G. Hitchon, Ralf Peter Brinkmann

DPG Früh­jahrs­ta­gung 2015, Bochum, Ger­ma­ny, 2-5 March


High Power Impulse Magnetron Sputtering (HiPIMS) is a novel Ionized Physical Vapor Deposition (IPVD) technique, able to achieve an ultra dense plasma with a high ionization degree among the sputtered atoms. This is accomplished by applying a large bias voltage to the target in short pulses with low duty cycle. The electrons emitted by the target because of the ion bombardment are accelerated in the cathode fall and reach the magnetized plasma bulk with a large energy. In this contribution we present an analytic calculation of the distribution function of these energetic electrons. The electrons are inserted into the system as a monoenergetic beam which slows down by Coulomb collisions with a Maxwellian distribution of bulk electrons, and by in- elastic collisions with neutrals. The results are verified for parameters appropriate to HiPIMS discharges, by comparing the analytic result with that of a numerical global model. We expect this work to be applicable to a variety of magnetron systems such as HiPIMS and dc discharges.